Protractor by Dollond, late 18th century

Rectangular protractor, late 18th century.
Rectangular protractor in brass, engraved "Dollond, London", late 18th century.As well as the usual angular scale the instrument contains a diagonal scale for plotting distances on a map or plan.
 
Currently on display in:
Mathematics
Year made :
late 18th century
Inventory number :
1915-388